subject: What Is A Meteorite? [print this page] What Is A Meteorite? What Is A Meteorite?
A meteorite is a natural object from space that impacts the earth. It can be anywhere in size from a speck of dust to an entire asteroid. Usually, a meteorite is a chunk of asteroid that has been broken off during a collision and sent hurtling through space.
Before a meteorite impacts the earth, it is considered a "meteor" or "meteoroid." It can't be classified as a "meteorite" until it hits. When these objects from space enter the earth's atmosphere, they become raging fireballs. Most of them burn up before they hit the ground. These burning meteoroids are what we see in the night sky as shooting stars or falling stars.
What Are Meteorites Made Of?
Meteorites are made of rock and metal. Like earth rocks, they can be composed of a variety of materials. Most of the meteorites that have been found contained high levels of nickel and iron. They can also have stones, silicates, sulfides, alloys and other materials.
Can Meteorites Be Predicted?
Unfortunately, they can't. However, scientists keep a close watch on objects in space and what they're doing. They know that a number of meteorites have come from asteroid collisions in the various asteroid belts in the solar system. The closest of these is between Mars and Jupiter. The study of "near earth objects" looks at the movements of these objects and assesses the threat level that they pose to earth.
Some scientists speculate that a massive meteorite may have impacted Mexico's Yucatan Peninsula 65 million years ago. While it's unlikely that the world will see a repeat of this event, it is possible that there will be smaller but no less damaging impacts in the future. The 1908 Tunguska Catastrophe is now believed by many to have been caused by a meteorite. In 1908, there was a mysterious explosion in the area near the Tunguska River and Lake Baikal that scorched the surrounding landscape and caused widespread damage. Scientists predict that a catastrophe like this could occur again, and this is why near earth objects are being studied carefully.
The Biggest Meteorite Ever Found
The world's biggest meteorite was discovered by a farmer in Namibia in 1920. He found a massive chunk of iron and nickel under his field. This meteorite is called "Hoba," named after the farm where it was found. Weighing a whopping 66 tons, it still sits in the exact spot where it was found, being too big and heavy to move. Hoba hit the earth around 80,000 years ago and strangely enough left no crater.
The biggest and best preserved meteorite crater is located at northern Arizona's Meteor Crater. This is the site where a meteorite hit the earth around 50,000 years ago. The crater is 550 feet deep and its rim stands 150 feet above the desert floor. Other large craters include Ghana's Bosumtwi, Canada's Deep Bay, the Aorounga impact crater of Chad and Australia's Gosses Bluff.
